Titanium base alloys containing aluminum and tin



Patented Feb. 16, l954 TITANIUM BASE ALLOYS CONTAINING ALUMINUM AND TIN Robert I. Jafiee, Worthington, and Horace R. Ogden and Daniel J. Maykuth, Columbus, Ohio, assignors, by mesne assignments, to Rem-Cru Titanium, Inc., Midland, Pa., a corporation of Pennsylvania No Drawing. Application April 29, 1952, Serial No. 285,076

is limited by its relatively low strength and high a cost, and it becomes desirable to alloy titanium with such other metals as will increase the strength to acceptable levels and preferably at the same time effect some reduction in the total material cost. Aluminum is a metal well suited to the attainment of these objectives. It is quite plentiful, has a low density, and has a material strengthening effect on titanium. However, the amount of aluminum alone that can be added to titanium is limited by its adverse effect on ductility. Binary alloys of titanium with more than about 5% of aluminum are too brittle for most structural uses; and such binary alloys containing less than about 5% of alumi- 4 Claims. (Cl. 75-177) regarded as additions of aluminum, with or withabout 1% to 23%, with the aluminum ranging from about 0.25 to 7.5% depending on the tin content, the aluminum being preferably on the low side when the tin is on the high side and vice versa. It has been found that these alloys, particularly those of relatively high tin content, not only have excellent properties when made from substantially pure titanium, but are characterized by a most unusual tolerance for the interstitial ingredients, carbon, oxygen and nitrogen. For example, an alloy of tin, 2% aluminum, 0.2% nitrogen, balance titanium, possesses a rare combination of high strength and good ductility.

For producing ductile titanium-tin-aluminum alloys in accordance with the invention, having good forging and rolling properties, the aluminum content is preferably related to the tin content substantially in accordance with the following proportions:

num do not possess sufiicient strength to be of 5 Table I general utility. A further strengthening, as well as an increase in the amount of relatively in- Aluminum expensive aluminum, is highly desirable. Tm The present invention, in one of its aspects,

comprises the discovery that the addition to 30 1 O'H titanium-aluminum alloys of a few percent of 8.5 :2 5

tin, effects a marked improvement in the properties of titanium-aluminum alloys of a given aluminum content, say 3.5% to 5%, and likewise enables an increase of the aluminum content up to about 7.5% with a material increase in strength, while maintaining adequate ductility.

The invention further contemplates, in its broader aspect, a series of alloys which may be 3 commercial titanium. Further controlled additions of the interstitials show some distinctive 4 annealed for 3% hours at 850 C., unless otherwise noted, are as follows:

Table II [Iodide titanium-base alloys] Composition, Percent (Balance Tensile Properties: p. s. l.X1,000

Titanium) Annealed Ultimate Elon gatlon A} Sn g' g g' 1 2; Strength 1", Percent Bend T o v 0 i 88- 37:" v on: 1 o 5 1 278 67 78" 7 5 .2. 312 81 88' 14 1.6 5 5 312 90 94 12 1. 1 5 2. 385 144 12 1.4 5 12. 404i: 145 12 1.6 5 2. 426:5 152 a 5 2. 427" 144 4 5 1. 394 149 9 4.4 3; 5 1; A2 :7. 389i: 151 13 4.2 1.3 890i 149 13 4.2 5 3.5 f 399"... 161 11 4.2 1 5 =5 391" 147 17 2.3 5 [7. 5. 398,, 110 0 6. 2 1 7. 5 1 357: 106 2. 8 7. 5 2. 5 324" 94" 101 16 1. 8 r 1.5 5 351 109; 11s 14 .7 37.5 '=7.'5 1 398 116'- 116 9 7.5 2.5 .253? g 392 136 138 10 2.3 3 7. 5 2. 5 393 132 132 9 6 1 Annealed 4 hours at 925 C 1 Annealed 3% hours at 2150 '0. plus 1 hour at 925. o. 1 Brittle.

eifects In==general;- the tolerance for' the inter stitialsi as; determined; by a ductility requisiteto broad an varied utility; is greater than that of most titanium-alloys, and this 181 particularly true'fofthose alloyswhichcontain a relatively smalh'amounfl'off-aluminum For example, in alloy containing notover 5 %"-tin and not overabout 2% aluminum, carbon may beadded up to gui's'hed from carbom-the tolerance for nitrogen diminishesfmore -slowly from: a maximum of about 3%" for .59; A I H I M very low-content-of--aluminum and tin to a value between- 0.l5%i and 0.19%"

which remains almost constant fora widerange of compositions. Oxygenpccupies an intermediate position, the tolerance therefor decreasing at' a more constant rate from a maximum of about{;0.51% The permissible ,oxygen content 01 an alloycontaining 13% tin, 3% aluminum is about -0.2

The alloys wofthis invention may. be. prepared.

by meltcastingin an-'atmosphere onargon,

rollingflata suitabletemperature, say,850 Onto;

980 C.,",and annealingunder conditions which will effect recrystallization but not substantial grain growth or re-solution of carbides. A typical vbut by. .no: means universal annealing treat.-

ment. comprises 1 soaking .at. a temperature 10f about 850.(3.-'ior.-from 2 to 3 -rhours.a- The rate of cooling-afterannealing is not-material,since in :these :alloys-...the-.titanium, :with the exceptions noted later, is all in the alpha phase except for minor amounts which may be combined as titanium-carbide.

The properties of selected alloys of titanium of requisite purity with aluminum and tin, as

In the foregoingtable; and those whichfollowfi bend ductility? is measured as the radius L upon which the alloy can be bent without .fra'cture to i.

an angle of 75, the radius bein'g stated as amul tiple of the specimen thickness.

Microscopic examination showsmost'of these. alloys to be of small.grainsize;'probablydue'to' a fine distribution oftarbides; Carbon'is less soluble inbeta titanium thanin alpha titanium,"

hence in a melt containing, say 0.2 carbon,'a sub stantial proportion of the carbon will be present as carbides,v which as the melt congeals are frozen in a matrixof beta titaniuminia fine'dispersion. As recrystallization proceeds" without substantial solution of carbides," the numerous? carbide particles ,form ,nucleatiomsites for. the 7 growth of relatively small alpha-grains, and ,in-i

hibit the-growth-jof large grains? Grain" sizes"? as small as 0.012 mm: and 0.0151mm. have been observed repeatedly; and the average grain'size.

is from about 0.020"mmi:to' 0.030- mm; Fine grain size and-the presence ofVisible-carbide-particle stringers -are"associatedwith the substantial clifierences between yield' strength and ultimate" strengthappearing in *the above table? This characteristic renders the alloys universally. useful, being particularly advantageous for *sheet'? and other formswhich are'stretcheddnfabricw' tion.

All ofthealloys whose -properties-are=tabu= lated in Table'II above contain a minimum 'of 5 iof aluminum and show embrittlement by -a tin content of-about 7.5%. A reduction-"of tile =1' aluminum content','-say-to '2%, greatly increases the tolerance for tin as well as for the inte stitials, enabling theuse of as-much *as' 23% "tin.

aluminum, and 0.2% nitrogen, has a 0.2% offset yield strength of 135,000, an ultimate strength of 142 000, with an elongation of 16% and a bend ductility of 2.1 T.

Other alloys containing varying amounts of Min. Bend '1 Min. Bend T Annealed Hardness, Vickers Annealed Hardness, Vickers are given in Tables Percent Reduction in Area.

Elongation to 1" Table IV-A Tensile Properties: p. s. i. X 1,000

Table I I I [Iodide-titanlum-base alloys] Tensile Properties: p. s. i. X 1,000

[Commercial-Purity Ti-Sn-Al alloys] U1 tim ate Strength argon for 2 hours at 850 C III, IV-A and IV-B below 20046057309110121066 154 8586 S 4 O 6 53557 237300596042749608492 H 0049 uoooodi mflwdfi b mnml 82 0 r 11 r 1 1 1. 1 111 1.11 l l 0.2% Offset Yield Percent (Balance Composition,

Titanium) s, and their r annealing in 1122335.0511223355555555-Lm11223355255- T522222 Composition, Percent (Balance Titanium) 5 5555 5 55 11111111L22222222222222223333333&5555TZmwwm 5 aluminum, tin and the interstitial properties as rapidly cooled af ze 1 liriule.

[Commercial-purity 'li-Sn-Al alloys with interstltlals] g Tensile Properties: p. s. l. 1 ,000

- Elong- Percent Annealed Sn Al O O N Offset EJ1533 3 atiou Reduction Hardness, Bend '1 H H Yield... 1 g tel .111 Area Vickers 1 1 128 133-" 16" 38' 422" 5.4

1 5 139 144 20 40 444 4 2.5; 1 5 0.1 120 129 16 39 393 g 3.4 1 1 5 0.2 129 136 21 36 431 5.1 1 1 5 0.1 129 135 14 35 1 384 3.5; 1' 2'. 5 136 l 141 18 I 35 423 4.7 5 2 5 0.1 3.. 128 136 12 23 437 1 2.6 I 2 5 0.2 127 133 17 34 423 Y 5.1 i 5 0.1 127 134 16 31 I 394 f 3.7 2.5 5 143 147 l9 33 438 i 6.6 2.5 5 141 f 143 22 37 422 I 6.4 1 2.5 5 0.2 137 142 16 -39 423 5.2 5 2. 5; 5 0.1 124 131 3 421 5.5 i 2.5 5 0.2 151 155 5 1 44 1 3- 5 138 141 19 33 421 4.8 i 3 5 140 144 17 29 4 421 V 4.5 3, 5 142 144 1 420 2.7 L 3 5 0.1 132 138 16 v 40 421; 1 5.2 1 3 5 0.2 139 143 16 31 424 3 5.1 5 0.1 122 128 6 12 g 392 1 1 5.6 8 g: 5 0.2 148 152 6 15 429 i I 4 5 130 134 20 43 5; 405 3 l 4.9 4 5 0.2 136 137 2 15 428 7.0 4,. 5 0.1 120 134 I 12 23 404 5 5.4 v 4 5 0.2 155 156 2 12 454 j i 5 1 105 108 j. 25 322 1.2 I 5". 1 0.2 .s. 100 19 42 348 1 3.3 1 E 5 1 0.2 127 135 21 38 373 2.0 1 2 113 22 49 34s 2.4 1 1 5 2 0.2 117 125 24 40 3 24 i 6. 2 0.3 125 132 19 40. 376 1; 2.4 5 3 L. 125 129 .20 46 363- l; 1.9 5 3 0.1 125 139 .16 31 391;, 1 4.8 1 5 3 0.2 l- 124 132 20 41 300 2.2 I 5 '3 0.3 131 147 16 31 413 6.6 1 5 3 0.4 151 155 6 12 431 1 I 3 142 146 .15 15 417 2.4 1 1 553 10313 of this invention, in general, will withstand prolonged aging at temperatures as high as 400 C. Without material embrittlement 55 hence, they are particularly adapted for use under high temperature conditions. Moreover, these.titanium-aluminum-tin alloys are susceptible to a variety of useful modifications by the addition of fractions of other metals. For example, some compositions are benefitted by the addition of 0.5% to 5% antimony. Typical alloys and their properties are:

Composition, Percent (Balance Titanium).

Tensile Properties: p. s. i. X 1.000

' V. H. N. Propor- 0.2% 011- Ultimate Elon atlon A1 Sn Sb Surface tional limit set Yield Strength ln l Bend T 5 y 2.5' 0.5 0.25 390 100 150 157 14 4.1 5 1 2.5 1.0v 0.25 403 130 137 138 17 2.1 5 2.5 1.5 0:25 418 I 131 143 144 5 5 1 2.5- 2.5 0.25 392 1129 142 143 3 1 5 2.5 5 0425 409 114 134 1 1 Brittle.

Bend T longation y desirable addition 0.2% Oif- Ultimate E set Yield Strength mgla tion Elongation -aluminum-tin base, being usable in aluminum-tin alloys containing 0.5%

Tensile Properties: p. s. i. X 1,000

Dor-

Bend T T d 1100 502553255 w aslaazariheze B a n m m 21 $34341 31 cc u 8 d m nm unmm Ultimate Elon Strength Tensile Properties: p. s. i. X 1,000

titaniumto 5% copper. The following are typical:

v. H. N. Pro

Surface tionallimlt Manganese is a particularl Ultimate Strength 0.27 onset lield tin and silver are as follows, the sil Tensile Properties: p. s. i. X 1,000

Proporto a titanium amounts from 0.25% amples are as follows 0.27 onset field The properties of selected alloys of titanium ver being added up to about v. H. N.

Surface tional limit 0.2% Off- Ultimate Elongation set Yield Strength Composition. Percent (Balance Titanium) Tensile Properties: p. s. i. X 1,000

Beryllium in amounts from 0.1% to 1% is a useful adidtion, particularly for forging and cast-' Propor- Composition, Percent (Balance Titanium) 1 Brittle.

Composition, Percent (Balance Titanium) V. H. N.

Surface tional limit ing alloys. Representative compositions and their properties are the following:

Bismuth is useful when added in amounts from 0.5% to 5%, as shown by the following T d 13 m ra B H .w a We at m h E 1 s n .i a s mn L11 P t s E e Hm m fi P Oi 0 .Y nan 2t L11 Av e mm 05 n R e T Wm L noon I mm 1H1 m fi M 1 375 nm and S o in 0 0 0 0 mm m .1 505 mmm B o LL 01km Cta n 555 5 M 222 df 6 6P m 555 I 1 Brittle.

Somewhat similar properties are found in aluminum,

Zirconium is useful in amounts from 0.5% to 1-23% tin, 0.25-7.5%

aluminum, the tin con- ,tent being related .to the; aluminumcontentmth- Composition, Percent (Balance Titanium) Tensile Properties: p. s. i. X 1,000

. V. H. N. Propor- 0.27 011- Ultimate Elongation A1 Sn Zr Surface tionallimit set field Strength in l V f I The aforesaid additions of one or more of antimony,.beryllium, bismuth, copper, manganese, silver and zirconium are preferably alloyed with a titanium-tin-aluminum base containing about 1 to.. 5% ,tin, and 0.Z 5 ,to 37.5 aluminum and optimally about.'3.5.to 7.5%,.jaluminum, The added elements aforesaid retain the alpha structure of the base alloy with the exception of beryllium, copper and manganese. Beryllium forms intermetallic compounds. Copper and manganese are beta promoting or forming elernenlflSn. d9. pending on the amount added, in addition to which the beta phase promoted by copper-precipitates an intermetallic compound during cooling much more so than the beta phase promoted by manganese.

The above described alloys comprising additions to the Ti-Al-Sn base of antimony, beryli mu opsn. an es silve n ea conium, are described and. claimed in ourcopending applications Serial No. 294,263, filed June 18, 1952, and Serial No. 400,744, filed December 28, 1953, both comprising continuations-in-part of this application. a

This application is a continuation-in-part of applicants previously filed applications,--Serial No. 151,314, filed March 22,. 1950; Serial-,Np. 209,905, filed February 7, 1951; Serial No. 253,564, filed October 27, 1951; and Serial Nos. 213,681 to 213,687, inc., all filed March2, 1951., All of the above applications have become abandoned.

What is claimed is:

1. A titanium base alloy containing about: 1-23% tin, 0.25-7.5% aluminum, characterized in being ductile and forgeable and in having a ten- 'sile strength at least 10% in excess of the unalloyed titanium base metal.

' 2. An alloy consisting of about: 1-23% tin, 0.25-7.5% aluminum, :up to 71% carbon,. up; to 0.5% oxygen, upto 0.3% nitrogen, and the balance titanium.

3. A titanium base alloy containing about:

in said ranges, substantially in conformity with the following tabulation:

Aluminum,

Tin, Percent V figment 1 Aluminum, Tm, Percent Kareem said alloy also containing up to"1"% carbon, up to 0.5 oxygemup to 0.3% nitrogen, and the balance titanium. A

ROBERT I. JAFFEE. HORACE R. OGDEN. DANIEL J. MAYKUTH.

References Cited in the file of this patent The Canadian Mining and Metallurgical Bulletin, January 1950, page 27.

fJournal of Metals, March 1950, page 498. 

1. A TITANIUM BASE ALLOY CONTAINING ABOUT: 1-23% TIN, 0.25-7.5% ALUMINUM, CHARACTERIZED IN BEING DUCTILE AND FORGEABLE AND IN HAVING A TENSILE STRENGTH AT LEAST 10% IN EXCESS OF THE UNALLOYED TITANIUM BASE METAL.
 2. AN ALLOY CONSISTING OF ABOUT: 1-23% TIN, 0.25-7.5% ALUMINUM, UP TO 1% CARBON, UP TO 0.5% OXYGEN, UP TO 0.3% NITROGEN, AND THE BALANCE TITANIUM. 